Physics

I was thinking... if something had a strong and far enough magnetic energy, enough to pull a human, then we could use magnets to move between point A and point B. Stupid idea? Probably.

CPT symmetry (charge, parity, time) is at heart of modern physics: However, it seems treated seriously only in scale of Feynman diagrams with a few particles - is it still valid for macroscopic physics? Feynman diagrams of Avogadro's scale numbers of particles? In other words, if preparing CPT(initial conditions), should they lead to CPT(their evolution) ... including time reversed causality direction? While it seems technically challenging to prepare CPT(initial conditions), in theory general relativity allows to prepare T(initial conditions) - by hypothetical Klein-bottle-like wormholes ( https://en.wikipedia.org/wiki/Non-orientable_wormhole ) e…

Hi. Please no not merge to a similar thread. A laser beam travels trough air, enters glass, then a rhodamine+ dye, changing its green wavelength to yellow : If the dye is a thin layer, should the green beam pass trough it as yellow ? Or, if the dye is 'sandwiched' between glass 'slides' , would it exit the second glass as yellow ? Will it be coherent and monochromatic ?

Good day. What is the name(s) of crystals that divide or multiply the wavelength on incident light, and light exits them at doubled (or halved) wavelength ? Any examples beyond DPSS lasers ?

It seems that a particle can be completely described by 1) mass, 2) charge 3) spin (or angular momentum) It seems that a black hole can be completely described by 1) mass, 2) charge 3) spin (or angular momentum) Is there a reason for this similarity ?

Unlike other sciences, physics can be hard to define. For instance, if we want to give other sciences definitions or short descriptions we could say this, biology is the study of squishy stuff that might smell bad, chemistry is the study of stuff that goes boom, geology is the study of rocks and stuff from the ground, astronomy is the study of the stuff that dots the sky, but what exactly is physics?

I have a question, born of necessity : I believe that simplicity should always be at the center of everything : complexity becomes a poison for intuition and truth, when it is a mental masturbation apt to feed the ego of scientists who do not seek universal truths, but elitist beliefs to feel superior regardless( or, simply, the need to feel important, which in itself is an understandable need, but not at the cost of truth and justice ); the ego must not be developed without putting truth, courage, justice, the critical and rebellious spirit, as its foundation; otherwise it will be moved by the need to lie, to omit, to adapt reality to his oasis of certainties that have n…

Neutrinos are ghostly subatomic particles existing in quantum superposition. Right now 100 billion neutrinos are passing through your thumbnail every second. 8.5 minutes ago they were in the heart of the Sun.

Hello, in my opinion objective reality exists and is the result of all science. I wanted to know or have opinions on the question whether it is valid to define material things in a way that is unusual but does not interfere with scientific facts i.e. contradict them and thus become invalid in objective reality. For example a defitiniton such as : "an atom is a molecule" would be invalid because it contradicts science. Now let's say I see an apple on a table. Would it be valid to say the following? "The apple I see also consists of the upper most atoms of the table". I think it is valid as a subjective opinion because it does not contra…

We know that convex lens converge light at a point, Is there any other shapes that could also converge light? What if a convex len has only one side circular while the other end is flattened, when the incident light enters the circular side, what will be the transmitted light?

Hello. A helium filled mylar balloon, loses pressure as the small He atoms sieves trough any envelope, as far as I understand. Sent aloft, when the He pressure inside the balloon equals the atmospheric, the balloon stops rising, as far as I understand. At certain altitude the differential pressures of gas filling the balloon and the atmospheric outside its envelope, nearly equalizes, reducing the He leak. But there is still some weight of the balloon. Do helium balloons last much, much longer aloft at high altitudes than at low altitudes or there is a factor am not considering ?

Few questions based on the analogy with light/sound waves. I suppose most cannot be answered strictly, but at least give me your hunches. 1. Should I expect that gravitational waves may reflect when they hit some sort 'wall'? Can such wall exist? Can we have phase-change and non-phase-change reflections? Can you suggest a 'wall' (either active or passive) that causes phase-change or non-phase-change reflection of gravitational wave? 2. I suppose gravitational waves can interfere? Is this a linear or non-linear process? 3. Can we imagine a standing gravitational wave? Can we imagine resonant cavities for gravitational waves (possibly allowing …

How do you think about it?

Hello. A weather radar operates at location R and emits to/receives and displays bounced signals from snowing points S. Beyond the snowing there is rain or sleet at E or more snow in the same direction. R----------------------S---SS---------SSS--------EEEE---E-EE--------SSS------ > If the radar signal bounces from the precipitation back 'reporting' the signal; how are the beyond places detected, if the outgoing signal is severely attenuated/bounced/impeded after crossing trough large distances with precipitation ? If relevant, take each - as a mile.

How can electrons of a circuit accelerate the LHC protons to the velocity of .99c when the max velocity of an electron is 10^6 m/s.

Stern-Gerlach experiment is often seen as idealization of measurement. Using strong magnetic field, it makes magnetic dipoles (of e.g. atoms) align in parallel or anti-parallel way. Additionally, gradient of magnetic field bends trajectories depending on this choice. Magnetic dipoles in magnetic field undergo e.g. Larmor precession due to τ=μ×B torque, unless μ×B=0 what means parallel or anti-parallel alignment. Precession means magnetic dipole becomes kind of antenna, should radiate this additional kinetic energy. Thanks to duality between electric and magnetic field, we can use formula for precessing electric dipole, e.g. from this article: Using wh…

Is it considered that there is a minimum parcel of time, or can it be divided infinitely to zero ?

Hello: I am "No-One" (named Ben, the "no-one is based on the idea that in the whole of time, 100 years is nothing. We are nothing, but what we leave for the future generations.), and "I am not me (more philosophy: One ends different than when one is born, evolved through the things the person experienced). I am 52 years young, Belgian, married now 30 years with my first and only love that I met at age 23, resulting in 4 daughters and a son (in that order). Blessed with severe Asperger's and severe ADHD, my life always evolved around the logical and rational, and I live to prevent issues by fixing these before these happen. Something I am decently skilled in,…

When I try to answer this question, I think of light traveling through the vacuum of empty space as photons. But if light is both a particle AND a wave, when light travels through space, it is a wave of WHAT? There is no medium, no ether, to transmit a wave.

Hello. We are trying to understand Physics of this new VAWT turbine device on Youtube: Video removed by moderator How air flow does work like this at this high rotation speed? It say "Wing turning with Aerodynamic Lift-Force" in text description but it is some kind of wind vortex used maybe? How vector the air pressure through it to keep so stable in fast wind? Is there Academic paper which explain aerodynamics simikar like this? We only find papers on rotating animal and insect wings so far. Thank you - Ahmad

If an object contains more electrons than protons it will become a negatively charged object is that right? Two questions here: In practical situation, how to make an object slightly negative charged? If I simply put a USB charging cable designed for mobile phone (connected to the mains) is it enough to make an object negatively charged? When an object becomes negatively charged, how will it end up? Do the electrons stay in the object long time or forever or do they go into air? or do they go to the ground?

Without doubt, white color should reflect sunlight while black color should absorb it. It's cooler to wear white clothes. How about protection against sunlight? It's said black is better because more sunlight is absorbed so that it won't reach our skin. I am confused, white color should reflect sunlight away from our skin, isn't it better?

There's a match in the physics' constants: h = k.q.c Does anybody knows the reason? h = 6,62 x10^-34 J/s k = 1,38x10^-23 J/K q = 1,60x10^-19 C c = 3,00x10^8 m/s These are the values with precision of two digits but the matching seems valid for any quantity of digits. Nothing appears in a google search...

This thread is aimed particularly at @hoola and @bangstrom It took from the mid 1600s to the late 1800s to appreciate the full significance of this difference and even today it is rarely brought out in courses. When schoolboys move up from the algebra of values eg solve x+3 = 8 to the calculus they are introduced to 'functions'. But few, if any, are taught that functions have an algebra of their own. And this algebra is different (more complicated) from the very simple algebra of values they have become accustomed to. The function and its derivative (short for derived function) have a particular property that they exist (mathematically) w…

Is there any alternative to nuclear energy? Long term, nuclear energy creates more problems than solutions. For many decades mankind has been trying to develop more efficient way of producing energy and tackle nuclear waste. Many scientific teams around the world hope to make some progress in this area. Billions of taxpayers money are being pumped into the research every year. Is there any chance for nuclear fussion technology to power our homes and businesses in the near future? Is there any chance for nuclear power plants to become obsolete? I want to start a serious discussion here about our future on this small planet. This thread is especially dedicated to thos…